JPH05171391A - Hot-dip zinc plated steel excellent in adhesive durability - Google Patents
Hot-dip zinc plated steel excellent in adhesive durabilityInfo
- Publication number
- JPH05171391A JPH05171391A JP33523091A JP33523091A JPH05171391A JP H05171391 A JPH05171391 A JP H05171391A JP 33523091 A JP33523091 A JP 33523091A JP 33523091 A JP33523091 A JP 33523091A JP H05171391 A JPH05171391 A JP H05171391A
- Authority
- JP
- Japan
- Prior art keywords
- hot
- dip galvanized
- thin film
- galvanized steel
- adhesive
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- Electroplating And Plating Baths Therefor (AREA)
- Coating With Molten Metal (AREA)
- Other Surface Treatments For Metallic Materials (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、溶融亜鉛めっき鋼材及
び合金化溶融亜鉛めっき鋼材 (以下、両者をあわせて溶
融亜鉛系めっき鋼材と総称する) に関する。より詳しく
は、本発明は低温 (−50℃〜０℃) 環境下での衝撃負荷
よるめっき皮膜の剥離に対する耐久性(低温耐衝撃剥離
性) が良好で、しかも接着耐久性に優れた、自動車、家
電製品、建材用途などに好適な溶融亜鉛系めっき鋼材に
関するものである。TECHNICAL FIELD The present invention relates to a hot-dip galvanized steel material and an alloyed hot-dip galvanized steel material (hereinafter, both are collectively referred to as hot-dip galvanized steel material). More specifically, the present invention provides an automobile having excellent durability (low temperature impact peel resistance) against peeling of a plating film due to impact load in a low temperature (-50 ° C to 0 ° C) environment, and also having excellent adhesion durability. , A hot-dip galvanized steel material suitable for home appliances, building materials, etc.
【０００２】[0002]
【従来の技術】溶融亜鉛めっき鋼材、例えば、溶融亜鉛
めっき鋼板は、通常、表面を清浄化した鋼板を弱酸化性
雰囲気もしくは還元雰囲気で予熱した後、水素＋窒素の
還元雰囲気で鋼板を加熱もしくは焼鈍し、しかる後、鋼
板をめっき温度付近まで冷却し、溶融亜鉛浴に浸漬する
ことにより製造される。また、合金化溶融亜鉛めっき鋼
材は、溶融亜鉛めっき鋼材をさらに 500〜600 ℃の材料
温度で３〜30秒加熱することにより、めっき層を少なく
とも部分的にFe−Zn合金としたものである。2. Description of the Related Art Hot-dip galvanized steel materials such as hot-dip galvanized steel sheets are usually prepared by preheating a steel sheet whose surface has been cleaned in a weak oxidizing atmosphere or a reducing atmosphere and then heating the steel sheet in a reducing atmosphere of hydrogen and nitrogen. It is manufactured by annealing and then cooling the steel sheet to a temperature near the plating temperature and immersing it in a molten zinc bath. The alloyed hot dip galvanized steel material is obtained by heating the hot dip galvanized steel material at a material temperature of 500 to 600 ° C. for 3 to 30 seconds to make the plating layer at least partially an Fe—Zn alloy.
【０００３】ところで、一般に溶融亜鉛めっき鋼材の低
温耐衝撃剥離性が低下する原因は、Fe／Zn界面に生成す
る硬くて脆いFe−Zn合金相にあるとされている。そこ
で、通常は、溶融亜鉛浴中のAl添加量を増やすことによ
って、Fe／Zn界面におけるFe−Zn−Al系三元合金層の生
成量を増加せしめ、過度のFe−Zn反応を抑制する対策が
採られている。しかしながら、浴中Al量を増やすと、め
っき皮膜の時効現象による経時的な密着性低下 (経時剥
離と呼ばれる) を生じやすい欠点がある。By the way, it is generally said that the cause of the low-temperature impact peeling resistance of hot-dip galvanized steel material is lowered is the hard and brittle Fe-Zn alloy phase formed at the Fe / Zn interface. Therefore, usually, by increasing the amount of Al added in the molten zinc bath, the amount of Fe-Zn-Al ternary alloy layer formed at the Fe / Zn interface is increased, and an excessive Fe-Zn reaction is suppressed. Has been taken. However, when the amount of Al in the bath is increased, there is a drawback that the deterioration of the adhesiveness with time due to the aging phenomenon of the plating film (called peeling with time) is likely to occur.
【０００４】合金化溶融亜鉛めっき鋼材については、過
度のFe−Zn反応によって生成する脆弱なΓ相が、めっき
皮膜の低温耐衝撃剥離性が低下する原因であるとされて
いる。したがって、従来からこのΓ相の生成抑制に努力
が注がれ、次のような方法が採用されている。一つは、
素地鋼材の化学組成を制限することによって、合金化過
程における過度のFe−Zn反応を抑制することである。例
えば、鋼中ＰはFe−Zn反応を抑制し、脆性体であるΓ相
の生成を防ぐ効果がある。また一方で、Fe−Zn反応を加
速させる鋼中元素もあり、これらの元素の使用を差し控
えるか、添加量を少なくする必要がある。この種の元素
としては、例えば、Ti、Mn等が挙げられる。しかしなが
ら、素地鋼材の化学組成を制限することは、当然鋼の機
械的性質を限定されたものとしてしまう。With respect to the alloyed hot-dip galvanized steel material, the brittle Γ phase produced by excessive Fe-Zn reaction is said to be the cause of the low-temperature impact peel resistance of the plating film being lowered. Therefore, efforts have conventionally been made to suppress the generation of the Γ phase, and the following method has been adopted. one,
It is to suppress the excessive Fe-Zn reaction in the alloying process by limiting the chemical composition of the base steel material. For example, P in steel has the effect of suppressing the Fe—Zn reaction and preventing the formation of the Γ phase, which is a brittle body. On the other hand, there are also elements in the steel that accelerate the Fe-Zn reaction, and it is necessary to refrain from using these elements or to reduce the addition amount. Examples of this type of element include Ti and Mn. However, limiting the chemical composition of the base steel naturally limits the mechanical properties of the steel.
【０００５】また、合金化過程を制御する方法も有効で
ある。例えば、合金化させる温度を通常より低く抑える
ことによって、延性に富むδ1 相単相からなるめっき皮
膜を生成させる方法が考えられる。この手法は有効では
あるが、製造ラインスピードを落とす結果につながるこ
とや、素地鋼材の鋼種によって制御条件を工夫しなけれ
ば、望まれるめっき皮膜構造、すなわちδ1 単相にする
ことは難しく、万全な方法ではない。A method of controlling the alloying process is also effective. For example, a method of generating a plating film composed of a δ 1 phase single phase rich in ductility can be considered by suppressing the alloying temperature lower than usual. Although this method is effective, it is difficult to achieve the desired plating film structure, that is, the δ 1 single phase, unless the control conditions are devised depending on the type of base steel material, which leads to the result of slowing down the production line speed. Not the right way.
【０００６】このように、溶融亜鉛めっき鋼材や合金化
溶融亜鉛めっき鋼材の低温耐衝撃剥離性を経済的に高い
方法で確保することは極めて難しい。低温での耐衝撃剥
離性は、Fe素地とめっき皮膜との結合力のみに依存する
ものではなく、衝突によりめっき皮膜中に発生したミク
ロクラックが伝播していき、Fe／めっき層界面で方向転
換して界面に沿ってクラックが集中して走るか否か、さ
らにはこの界面近傍の極薄い部分のめっき層の耐破壊性
が決定的要因と考えられており、その理論的解明は未だ
暗中模索の段階にある。しかも、このように変形、破壊
しためっき皮膜が塩水環境での乾湿繰り返し腐食を行っ
た際に示す衝撃疵部の耐ブリスター、赤錆防錆能の如何
が、総合的実用性に関して重要な因子を構成している。As described above, it is extremely difficult to secure the low temperature impact peel resistance of the hot dip galvanized steel material and the alloyed hot dip galvanized steel material in an economically high method. Impact peeling resistance at low temperature does not depend only on the bonding force between the Fe substrate and the plating film, but microcracks generated in the plating film propagate by collision and change direction at the Fe / plating layer interface. Therefore, it is considered that the cracks concentrate and run along the interface, and the fracture resistance of the plating layer in the very thin part near this interface is the decisive factor. Is in the stage of. In addition, the blistering resistance of the impact flaws and the red rust proofing ability, which are shown when the deformed and destroyed plating film is subjected to repeated dry and wet corrosion in a salt water environment, are important factors for overall practicality. is doing.
【０００７】室温付近における単なるFe素地／めっき層
界面での密着性改善を図る手段として、鋼板などの鋼材
にFe等の純金属を極薄でプレめっきすることは公知であ
る。鋼板に予め純Feめっきする技術は、例えば、特開昭
57−79160 号、同57−70268号、同58−120772号に記載
されている。溶融めっき前にFeめっきを施して得た溶融
亜鉛めっき鋼材は、施さない場合に比べて、めっき皮膜
の室温での密着性向上はある程度みられるものの、低
温、高速で小石等があたる低温衝撃に対する剥離耐久性
については全く不十分であった。合金化溶融亜鉛めっき
鋼材についても同様のことが言える。As a means for improving the adhesion at a mere Fe base / plating layer interface near room temperature, it is known to preplate a steel material such as a steel sheet with an extremely thin pure metal such as Fe. A technique for pre-plating pure Fe on a steel sheet is disclosed in
57-79160, 57-70268 and 58-120772. The hot-dip galvanized steel material obtained by applying Fe plating before hot dip coating has some improvement in the adhesion of the plating film at room temperature compared to the case where it is not applied, but it is resistant to low temperature impacts such as pebbles at low temperature and high speed. The peeling durability was completely insufficient. The same applies to the galvannealed steel material.
【０００８】一方、近年、接着技術が向上したことか
ら、溶接部の耐食性低下や溶接部の外観不良 (溶接痕の
形成) の問題の改善を図る目的、或いは溶接不可または
困難な材料種や部位への適用を図る目的で、溶接に代わ
る鋼材の接合手法として接着手法が注目されている。接
着により鋼材を接合する場合、接着初期における接着部
界面の密着強度 (以下、初期接着性という) および腐食
環境下における接着部界面の密着強度の低下抑制 (以
下、接着耐久性という) が重要であり、これらに優れた
めっき鋼材が求められている。On the other hand, in recent years, since the bonding technique has been improved, the purpose of improving the corrosion resistance of the welded part and the problem of poor appearance of the welded part (formation of weld marks), or the kind or part of the material that cannot be welded or is difficult For the purpose of applying to steel, the bonding method has attracted attention as a method of joining steel materials instead of welding. When joining steel materials by gluing, it is important to suppress the adhesive strength at the adhesive interface at the initial stage of adhesion (hereinafter referred to as initial adhesiveness) and the reduction of the adhesive strength at the adhesive interface in a corrosive environment (hereinafter referred to as adhesive durability). Therefore, there is a demand for plated steel materials having excellent properties.
【０００９】この初期接着性や接着耐久性については、
近年になって種々の研究がなされてきた。亜鉛めっきを
代表とする犠牲防食皮膜を有する表面処理鋼板は、一般
に冷延鋼板に比べて初期接着性に劣り、また接着耐久性
についても、腐食の進行に伴ってその接着強度の絶対値
は低下するため、実際の使用に際しての接着耐久性は十
分であるとは言い難かった。Regarding the initial adhesiveness and adhesive durability,
In recent years, various studies have been made. Surface-treated steel sheets having a sacrificial anticorrosion coating, typified by zinc plating, are generally inferior in initial adhesiveness to cold-rolled steel sheets, and also in terms of adhesion durability, the absolute value of the adhesive strength decreases as corrosion progresses. Therefore, it has been difficult to say that the adhesive durability in actual use is sufficient.
【００１０】溶融亜鉛系めっき鋼材の初期接着性が冷延
鋼板よりも劣る原因は、めっき皮膜中に脆性体である前
記Γ相等が存在すると、剪断引張時にその部位で剥離が
起こるために見かけ上の接着強度が低い結果となること
や、鋼材素地とめっき皮膜界面の密着力が低いことによ
ると考えられる。従って、初期接着性の改善は、このよ
うな脆性体の生成を可及的に少なくすること、例えば、
熱処理条件の制御によって引張強度を増加することや、
めっき前処理による被めっき材表面の活性化を十分に行
うことにより可能となる。しかし、腐食の進行に伴って
発生する接着強度の劣化の改善、即ち、接着耐久性の向
上は、このような手段では達成することができない。The reason why the initial adhesiveness of the hot-dip galvanized steel material is inferior to that of the cold-rolled steel sheet is that the presence of the brittle body, such as the Γ phase, in the plating film causes the peeling at that portion during shear tension, which is apparently the cause. It is thought that this is due to the low adhesion strength of the steel and the low adhesion between the steel substrate and the plating film interface. Therefore, the improvement of the initial adhesion is to reduce the formation of such brittle bodies as much as possible, for example,
To increase the tensile strength by controlling the heat treatment conditions,
This can be achieved by sufficiently activating the surface of the material to be plated by the pretreatment of plating. However, the improvement of the deterioration of the adhesive strength caused by the progress of corrosion, that is, the improvement of the adhesive durability cannot be achieved by such means.
【００１１】[0011]
【発明が解決しようとする課題】本発明の目的は、上記
した従来技術の問題点を克服し、低温耐衝撃剥離性に優
れ、しかもスポット溶接法に代わる接合法である接着接
合法で接合した時の接着性が、初期接着性のみならず経
時的な密着性低下である接着耐久性についても大幅に改
善された溶融亜鉛系めっき鋼材を提供することである。DISCLOSURE OF THE INVENTION The object of the present invention is to overcome the problems of the prior art described above, to bond by an adhesive bonding method which is excellent in low temperature impact peeling resistance and which is an alternative to the spot welding method. It is an object of the present invention to provide a hot-dip galvanized steel material in which not only the initial adhesiveness but also the adhesive durability, which is a decrease in adhesiveness over time, is significantly improved.
【００１２】[0012]
【課題を解決するための手段】本発明者らは、低温耐衝
撃剥離性と、接着性、特に接着耐久性に優れた溶融亜鉛
系めっき鋼材を実現すべく鋭意検討を重ねた結果、鋼材
素地上に、下地層として微小クラックを無数に有する亜
鉛系合金電気めっきの薄膜層を形成し、この下地層の上
に溶融亜鉛めっきを施すことにより、上記の望ましい特
性を備えた溶融亜鉛系めっき鋼材が安定して得られるこ
とを見出し、本発明を完成させた。Means for Solving the Problems The inventors of the present invention have conducted extensive studies to realize a hot dip galvanized steel material excellent in low-temperature impact peeling resistance and adhesiveness, particularly adhesion durability, and as a result, A zinc-based alloy electroplating thin film layer having an infinite number of microcracks is formed on the ground as a base layer, and hot dip galvanizing is performed on the base layer to provide the above-mentioned desirable characteristics of the galvanized steel material. Was found to be stably obtained, and the present invention was completed.
【００１３】ここに、本発明の要旨は、平均クラック幅
が 0.001〜5.0 μｍの微小クラックがクラック面積分率
で５〜80％の密度で存在する亜鉛系合金電気めっき薄膜
層を下地層として持つことを特徴とする、低温耐衝撃剥
離性が良好で接着耐久性にも優れた溶融亜鉛系めっき鋼
材にある。Here, the gist of the present invention is to provide a zinc-based alloy electroplating thin film layer having microcracks having an average crack width of 0.001 to 5.0 μm at a density of 5 to 80% in terms of crack area fraction as an underlayer. A hot-dip galvanized steel material having excellent low temperature impact peel resistance and excellent adhesion durability.
【００１４】[0014]
【作用】以下、本発明の構成をその作用とともに詳述す
る。本発明の溶融亜鉛系めっき鋼材の母材は、冷延鋼板
のような鋼板が最も一般的であるが、これに限定される
ものではなく、型鋼、棒材、管材などでもよい。The function of the present invention will be described in detail below together with its operation. The base material of the hot-dip galvanized steel material of the present invention is most commonly a steel sheet such as a cold-rolled steel sheet, but is not limited to this, and may be shaped steel, bar material, pipe material and the like.
【００１５】本発明のめっき鋼材の特徴は、溶融亜鉛め
っき皮膜の下地層として、平均クラック幅が 0.001〜5.
0 μｍで、クラック密度がクラック面積分率で５〜80％
の微小クラックが存在する亜鉛系合金電気めっき薄膜層
を有することである。下地薄膜層の微小クラックの幅と
密度がこの範囲内である場合に、溶融亜鉛系めっき皮膜
の低温耐衝撃剥離性および接着耐久性がともに著しく改
善される。The characteristic feature of the plated steel material of the present invention is that the average crack width is 0.001 to 5.
At 0 μm, crack density is 5-80% in terms of crack area fraction
The present invention is to have a zinc-based alloy electroplating thin film layer in which microcracks are present. When the width and density of the microcracks in the underlying thin film layer are within these ranges, both the low temperature impact peel resistance and the adhesion durability of the hot dip galvanized coating are significantly improved.
【００１６】下地薄膜層の微小クラックは、溶融亜鉛系
めっきの密着性の改善に極めて重大な影響を及ぼす。そ
の機構は明確ではないが、微小クラックを有する下地薄
膜層が外部からの衝撃に対して衝撃力の吸収（クッショ
ン）層になるため、低温耐衝撃剥離性が向上すること、
および、微小クラックを有する亜鉛系合金電気めっき薄
膜層が、上層として施される溶融亜鉛めっきの界面合金
化挙動に影響を与えるため、接着耐久性を維持できる密
着性に優れた界面構造を形成できることが寄与している
ものと推察される。この微小クラックの幅の平均値が0.
001 μｍ未満か、5.0 μｍ超では、このような効果が顕
著にはみられないため、下地薄膜層の微小クラックの幅
を、平均で 0.001〜5.0 μｍと限定した。The microcracks in the underlying thin film layer have a very serious influence on the improvement of the adhesion of the hot-dip zinc-based plating. Although the mechanism is not clear, the low temperature impact peeling resistance is improved because the underlying thin film layer having microcracks serves as a cushioning layer for absorbing impact force against external impact,
Also, since the zinc-based alloy electroplating thin film layer having microcracks affects the interfacial alloying behavior of the hot-dip galvanizing applied as the upper layer, it is possible to form the interfacial structure with excellent adhesion capable of maintaining the adhesion durability. Is believed to have contributed. The average width of these microcracks is 0.
If it is less than 001 μm or more than 5.0 μm, such an effect is not remarkable, so the width of the microcracks in the underlying thin film layer is limited to 0.001 to 5.0 μm on average.
【００１７】また、下地薄膜層における微小クラックの
存在密度も、低温耐衝撃剥離性および接着耐久性の改善
に大きな影響を与える。即ち、微小クラック密度が下地
層の全面積の５％未満では、有効な衝撃力吸収効果が発
揮できず、逆に80％超では界面合金化挙動に十分な影響
を及ぼすことができないため、低温耐衝撃剥離性と接着
耐久性を両立することができない。そのため、下地薄膜
層の微小クラック密度を５〜80％と限定した。The existence density of minute cracks in the underlying thin film layer also has a great influence on the improvement of low temperature impact resistance and adhesion durability. That is, if the microcrack density is less than 5% of the total area of the underlayer, an effective impact force absorption effect cannot be exhibited, and conversely, if it exceeds 80%, the interfacial alloying behavior cannot be sufficiently affected, so that low temperature It is not possible to achieve both impact peel resistance and adhesion durability. Therefore, the fine crack density of the underlying thin film layer is limited to 5 to 80%.
【００１８】なお、微小クラック密度（面積分率）は、
倍率5000Ｘの電子顕微鏡写真を縦10×横10で 100等分
し、各マスのクラックの有無を調べて、クラックのある
マス目の数を求めることにより測定される。The fine crack density (area fraction) is
It is measured by dividing an electron micrograph at a magnification of 5000 × into 100 equal parts of 10 × 10 and checking for the presence of cracks in each cell, and determining the number of cells with cracks.
【００１９】下地層の亜鉛系合金電気めっき薄膜は、亜
鉛含有量が70〜99重量％の範囲内のものが好ましい。こ
の下地薄膜層に存在させる合金元素は特に制限されるも
のではなく、例えば、Ni、Co、Cr、Mnのうちの１種もし
くは２種以上を使用できる。また、下地薄膜層の付着量
も特に制限されないが、 0.1〜10 g/m2 の範囲内が好ま
しい。付着量が0.1 g/m2未満であると、生成する微小ク
ラックの密度および厚みが少なすぎて、低温耐衝撃剥離
性と接着耐久性の改善効果が不十分となることがある。
一方、付着量が10 g/m2 を超えると、下地層の亜鉛系合
金めっき皮膜が緻密になり、微小クラックを発生させる
ことが困難となる。The zinc-based alloy electroplating thin film of the underlayer preferably has a zinc content in the range of 70 to 99% by weight. The alloying element to be present in this underlying thin film layer is not particularly limited, and for example, one or more of Ni, Co, Cr and Mn can be used. The amount of the underlying thin film layer attached is not particularly limited, but is preferably in the range of 0.1 to 10 g / m 2 . When the adhesion amount is less than 0.1 g / m 2 , the density and thickness of the generated microcracks may be too small, and the effect of improving low temperature impact peel resistance and adhesion durability may be insufficient.
On the other hand, when the adhesion amount exceeds 10 g / m 2 , the zinc-based alloy plating film of the underlayer becomes dense and it becomes difficult to generate minute cracks.
【００２０】下地層の微小クラックを有する亜鉛系合金
電気めっき薄膜は各種の方法で形成することができる。
例えば、母材の鋼材に亜鉛系合金電気めっきを、例え
ば、硫酸塩浴などの酸浴を使用して通常の電気めっき方
法で施し、その後、同一の電気めっき浴またの他の酸液
中に無通電浸漬するか、または電解液中で陽極電解によ
りめっきを部分的に溶解することにより微小クラックを
発生させる。浸漬温度および時間、または陽極電解条件
を適当に設定することにより、微小クラックの幅と存在
密度を本発明で規定する範囲内に調整することができ
る。或いは、電気めっきを、一定の時間通電を停止する
ＤＣパルス、または一定間隔で極性を反転させるＡＣパ
ルスなどのパルス電解により行うことにより、微小クラ
ックを有する亜鉛系合金電気めっき皮膜を直接形成する
こともできる。The zinc-based alloy electroplating thin film having minute cracks in the underlayer can be formed by various methods.
For example, zinc-based alloy electroplating is applied to the base steel material by a normal electroplating method using, for example, an acid bath such as a sulfate bath, and then the same electroplating bath or another acid solution is applied. Microcracks are generated by immersing without electric current or by partially dissolving the plating by anodic electrolysis in an electrolytic solution. By appropriately setting the immersion temperature and time, or the anodic electrolysis conditions, the width and density of the microcracks can be adjusted within the ranges specified in the present invention. Alternatively, the zinc-based alloy electroplating film having fine cracks is directly formed by performing electroplating by pulse electrolysis such as DC pulse for stopping energization for a certain period of time or AC pulse for reversing the polarity at certain intervals. You can also
【００２１】本発明の溶融亜鉛系めっき鋼材は、めっき
下地層として上記の微小クラックを有する亜鉛系合金電
気めっき薄膜を有する以外は、従来の溶融亜鉛めっき鋼
材または合金化溶融亜鉛めっき鋼材と同様でよい。上層
の溶融亜鉛系めっき皮膜は、下地薄膜層を形成した鋼材
に、常法に従って、適当な清浄化および活性化処理後に
溶融亜鉛めっきを施し、必要であればさらに合金化処理
を行うことによって形成される。溶融亜鉛めっき皮膜の
付着量は特に制限されないが、好ましくは、片面当たり
20〜200 g/m2である。溶融亜鉛めっき浴の組成、例え
ば、Al濃度にも特に制限はない。本発明の「溶融亜鉛め
っき」は、Zn−55wt％Al浴あるいはZn−５wt％Al浴を用
いるような溶融亜鉛合金めっきをも包含するものであ
る。このような亜鉛合金の溶融めっきに対しても、本発
明の下地薄膜層は低温耐衝撃剥離性と接着耐久性の改善
効果を発揮できる。The hot-dip galvanized steel material of the present invention is the same as the conventional hot-dip galvanized steel material or alloyed hot-dip galvanized steel material, except that it has the above-mentioned zinc-based alloy electroplating thin film having fine cracks as a plating underlayer. Good. The upper hot-dip galvanized film is formed by applying the hot-dip galvanization after appropriate cleaning and activation treatment to the steel material on which the base thin film layer is formed, and then further alloying it if necessary. To be done. The amount of the hot-dip galvanized film deposited is not particularly limited, but preferably per one side
20-200 g / m 2 . There is no particular limitation on the composition of the hot-dip galvanizing bath, for example, the Al concentration. The "hot dip galvanizing" of the present invention also includes hot dip galvanizing such as using a Zn-55 wt% Al bath or a Zn-5 wt% Al bath. Even for such hot dip galvanizing of zinc alloy, the underlying thin film layer of the present invention can exert the effect of improving low temperature impact resistance and adhesion durability.
【００２２】[0022]
【実施例】以下、実施例により本発明を具体的に説明す
る。実施例中、％は特にことわりのない限り、重量％で
ある。EXAMPLES The present invention will be specifically described below with reference to examples. In the examples,% is% by weight unless otherwise specified.
【００２３】〔めっき母材〕表１に示す組成の鋼板を10
0 mm×250 mm×0.8 mmに裁断し、溶剤洗浄後、めっき母
材に用いた。[Plating base metal] 10 steel plates having the composition shown in Table 1
It was cut into 0 mm × 250 mm × 0.8 mm, washed with a solvent, and used as a plating base material.
【００２４】[0024]
【表１】 [Table 1]
【００２５】〔下地薄膜層の形成〕下地薄膜層は、表２
に示すように合金元素としてNi、Co、CrまたはMnを含有
する亜鉛合金電気めっき層であり、硫酸酸性浴 (pH 1〜
３、温度40〜60℃) を用いた10〜100A/dm2の電流密度で
の電気めっき後の無通電浸漬もしくは陽極溶解、或いは
ＡＣパルス電解もしくはＤＣパルス電解のいずれかの方
法により、硫酸塩浴を用いて微小クラックを有する電気
めっき皮膜を母材鋼板の両面に形成した。めっき付着量
は通電時間の制御により調整した。得られた下地薄膜層
の微小クラックの状況、即ち、平均クラック幅とクラッ
ク密度を、5000倍のＳＥＭ写真によりクラック幅を測定
して平均クラック幅を求め、また前記写真を縦10×横10
に100等分し、クラックのあるマス数をクラック密度と
することにより求めた。[Formation of Base Thin Film Layer] The base thin film layer is shown in Table 2.
It is a zinc alloy electroplating layer containing Ni, Co, Cr or Mn as an alloy element as shown in, and a sulfuric acid acid bath (pH 1 to
3, non-conducting immersion or anodic dissolution after the electroplating at a current density of 10 to 100 A / dm 2 using a temperature 40 to 60 ° C.), or by any method AC pulse electrolysis or DC pulse electrolysis, sulfate An electroplating film having fine cracks was formed on both sides of the base steel sheet using a bath. The coating amount was adjusted by controlling the energization time. The state of the microcracks in the obtained underlying thin film layer, that is, the average crack width and the crack density, the crack width was measured by a SEM photograph of 5000 times to obtain the average crack width, and the photograph was measured in a length of 10 × width of 10.
It was obtained by dividing into 100 equal parts and dividing the number of cracked masses into the crack density.
【００２６】〔溶融亜鉛めっきおよび合金化処理〕下地
薄膜層を形成した鋼板を弱酸化雰囲気中で300 ℃に１秒
間加熱した後、窒素＋水素還元雰囲気中で750 ℃に20秒
間加熱して、表面を活性化した。次いで、0.1 ％のAlを
含有する460 ℃に保持された溶融亜鉛めっき浴中に３秒
間浸漬し、片面当たり60 g/m2 の溶融亜鉛めっきを両面
に施した。さらに一部のめっき鋼板は、溶融亜鉛めっき
に続いて、500 ℃で亜鉛の金属光沢が消失するまで合金
化処理した。[Hot-dip galvanizing and alloying treatment] The steel sheet on which the underlying thin film layer was formed was heated at 300 ° C for 1 second in a weak oxidizing atmosphere, and then at 750 ° C for 20 seconds in a nitrogen + hydrogen reducing atmosphere, The surface was activated. Then, it was immersed for 3 seconds in a hot dip galvanizing bath containing 0.1% Al and maintained at 460 ° C., and 60 g / m 2 hot dip galvanizing was applied to each side. Further, some of the coated steel sheets were subjected to hot dip galvanizing and then alloyed at 500 ° C. until the metallic luster of zinc disappeared.
【００２７】得られた溶融亜鉛めっき鋼材または合金化
溶融亜鉛めっき鋼板について、低温耐衝撃剥離性と接着
耐久性を下記の方法で評価した。The hot-dip galvanized steel material or alloyed hot-dip galvanized steel sheet thus obtained was evaluated for low temperature impact peel resistance and adhesion durability by the following methods.
【００２８】〔低温耐衝撃剥離性評価方法〕供試材 (70
×150 mm) の片面のめっき皮膜上に、リン酸亜鉛処理
(Chemfil 社、CF168 処理液使用) →カチオン電着塗装
(PPG 社、UniprimeTM塗料使用、膜厚30μm)→中塗り塗
装 (同社製エポキシエステル系塗料使用、膜厚15μm)→
上塗り塗料 (同社製アクリル・エナメル系塗料使用、膜
厚45μm)という手順で化成処理と塗装を行った。これを
供試台上にセットし、−20℃の低温条件下においてダイ
ヤモンド粒 (直径約３mm) を時速170 km/hの速度で10箇
所衝突させる衝撃を与えた後、次に述べる耐食性暴露試
験に供した。衝撃を付与した供試材を、１ヵ月に１回の
頻度で３％NaCl水溶液に30分間浸漬しながら、工業地帯
環境 (兵庫県尼崎市) に５年間にわたって暴露した。確
性評価は、５年間暴露した後の衝突点での塗膜ブリスタ
ーの最大径を測定し、この最大径が５mm以上のもの
(×) 、３mm以上で５mm未満のもの (△) 、１mm以上で
３mm未満のもの (○) 、１mm未満のもの (◎) という基
準で評価した。[Low-temperature impact peel resistance evaluation method] Test material (70
(× 150 mm), zinc phosphate treatment on one side plating film
(Chemfil, using CF168 treatment liquid) → Cationic electrodeposition coating
(PPG, using Uniprime TM paint, film thickness 30 μm) → Intermediate coating (using the company's epoxy ester paint, film thickness 15 μm) →
Chemical conversion treatment and coating were performed by the procedure of top-coat paint (using acrylic / enamel-based paint made by the same company, film thickness 45 μm). This was set on the test bench, and a shock was applied to the diamond particles (diameter about 3 mm) at 10 points at a speed of 170 km / h at a low temperature of −20 ° C., and then the corrosion resistance exposure test described below. I went to The impacted test material was exposed to an industrial zone environment (Amagasaki City, Hyogo Prefecture) for 5 years while being immersed in a 3% NaCl aqueous solution once a month for 30 minutes. The accuracy evaluation measures the maximum diameter of the coating film blister at the collision point after exposure for 5 years, and the maximum diameter is 5 mm or more.
Evaluation was made based on the criteria of (x), 3 mm or more and less than 5 mm (△), 1 mm or more and less than 3 mm (○), and less than 1 mm (⊚).
【００２９】〔接着性評価方法〕実施例で得ためっき鋼
板から採取した幅25mm×長さ100 mmの供試材を２枚１組
として、図１に示すように接着剤を介してめっき面を重
ね合わせ、 175℃×30分の加熱により接着剤を乾燥し
て、接着による単純重ね合わせ継手 (JIS-K 6850に準ず
る) を作製した。この接着試料に、リン酸塩化成処理と
カチオン電着塗装を施した後、図２に示す複合腐食試験
（塩水環境下での乾湿繰り返し腐食試験）に供した。こ
の腐食試験中、10サイクル毎に試料を取り出し、剪断引
張試験により接着耐久性を評価した。[Adhesiveness Evaluation Method] A set of two test pieces each having a width of 25 mm and a length of 100 mm taken from the plated steel sheet obtained in the example was used as a set, and a plated surface was provided with an adhesive as shown in FIG. Were piled up, and the adhesive was dried by heating at 175 ° C. for 30 minutes to produce a simple lap joint by adhesion (according to JIS-K 6850). This adhesive sample was subjected to a phosphate chemical conversion treatment and cationic electrodeposition coating, and then subjected to a complex corrosion test (dry / wet repeated corrosion test in a salt water environment) shown in FIG. During this corrosion test, a sample was taken out every 10 cycles and the adhesion durability was evaluated by a shear tensile test.
【００３０】接着に用いた接着剤は、１液型エポキシ系
接着剤であるアラルダイトTMXB3062(日本チバガイギー
製) であり、厚みが100 μｍとなるように接着した。接
着部は幅×25mmとした。リン酸塩化成処理とカチオン電
着塗装を施したのは、非接着面 (非めっき面)からの腐
食による接着耐久性への悪影響を除くためである。リン
酸塩化成処理とカチオン電着塗装は、カチオン電着塗装
の膜厚を10μｍとした以外は、上記の低温耐衝撃剥離性
試験と同様に実施した。The adhesive used for adhesion was Araldite ™ XB3062 (manufactured by Ciba Geigy), which is a one-pack type epoxy adhesive, and was adhered so that the thickness was 100 μm. The bonded portion had a width of 25 mm. The reason why the phosphate chemical conversion treatment and the cationic electrodeposition coating are applied is to remove the adverse effect on the adhesion durability due to the corrosion from the non-bonded surface (non-plated surface). The phosphate chemical conversion treatment and the cationic electrodeposition coating were carried out in the same manner as the above-mentioned low temperature impact peel resistance test except that the thickness of the cationic electrodeposition coating was 10 μm.
【００３１】引張試験は、25℃で引張速度50 m/minで行
った。接着性の評価は、剥離面中の接着剤が凝集破壊し
た部分の面積率 (目視により測定) に基づき、下記基準
で行った。なお、接着剤の凝集破壊による剥離の面積率
が高いほど、接着性が良好である。 ◎：100 ％、 ○：90％以上、 △：70％以
上、 ×：50％以上、 ××：50％未満。The tensile test was carried out at 25 ° C. and a tensile speed of 50 m / min. The adhesiveness was evaluated according to the following criteria based on the area ratio (measured by visual inspection) of the part of the peeled surface where the adhesive cohesively failed. The higher the area ratio of peeling due to cohesive failure of the adhesive, the better the adhesiveness. ◎: 100%, ○: 90% or more, △: 70% or more, ×: 50% or more, XX: less than 50%.
【００３２】次の表２に、下地薄膜層の形成方法とその
微小クラックの状況、上層の溶融亜鉛系めっき層の種
類、ならびに試験結果 (低温耐衝撃剥離性と接着耐久
性) についてまとめて示す。表２から明らかなように、
下地層の亜鉛系合金電気めっき薄膜の微小クラックの平
均クラック幅と密度のいずれかが本発明の範囲外である
と、低温耐衝撃剥離性と接着耐久性に関する改善効果が
得られない。Table 2 below summarizes the method of forming the underlying thin film layer, the state of its microcracks, the type of the upper hot-dip galvanized layer, and the test results (low temperature impact resistance and adhesion durability). .. As is clear from Table 2,
If either the average crack width or the density of the microcracks of the zinc-based alloy electroplating thin film of the underlayer is outside the scope of the present invention, the effect of improving low temperature impact peel resistance and adhesion durability cannot be obtained.
【００３３】[0033]
【表２】 [Table 2]
【００３４】[0034]
【発明の効果】以上述べたように、本発明によれば、低
温衝撃負荷に対する皮膜耐久性 (低温耐衝撃剥離性) に
優れ、さらに初期接着性のみならず接着耐久性にも優れ
た溶融亜鉛めっき鋼材および合金化溶融亜鉛めっき鋼材
が得られる。また、下地薄膜層もめっき層であるため、
溶接性は悪影響を受けない。従って、本発明の方法によ
り製造された溶融亜鉛系めっき鋼材は、例えば、自動車
の車体用にも有用であるが、接着耐久性に優れているこ
とから、特に接着剤での組立て割合が多い家電製品や建
材などに適用した場合に、その寿命を著しく増大させる
ことができ、産業上極めて有用である。As described above, according to the present invention, molten zinc having excellent film durability against low-temperature impact load (low-temperature impact peeling resistance) and excellent not only initial adhesiveness but also adhesive durability. A galvanized steel and a galvannealed steel are obtained. Also, since the underlying thin film layer is also a plating layer,
Weldability is not adversely affected. Therefore, the hot-dip galvanized steel material produced by the method of the present invention is also useful, for example, for automobile bodies, but it is excellent in adhesion durability, and therefore household appliances that are particularly assembled with adhesives are often used. When applied to products, building materials, etc., the service life can be remarkably extended, which is extremely useful industrially.
【図１】接着耐久性の評価に用いた、単純重ね合わせ継
手の形状を示す斜視図である。FIG. 1 is a perspective view showing a shape of a simple lap joint used for evaluation of adhesion durability.
【図２】接着耐久性の評価試験で採用した複合腐食試験
の工程と条件を示した説明図である。FIG. 2 is an explanatory diagram showing steps and conditions of a complex corrosion test adopted in an adhesion durability evaluation test.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 足立 吉隆 大阪市中央区北浜４丁目５番33号 住友金 属工業株式会社内 (72)発明者 中森 俊夫 大阪市中央区北浜４丁目５番33号 住友金 属工業株式会社内 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Yoshitaka Adachi 4-533 Kitahama, Chuo-ku, Osaka City Sumitomo Metal Industries, Ltd. (72) Inventor Toshio Nakamori 4-53 Kitahama, Chuo-ku, Osaka Sumitomo Metal Industries Co., Ltd.
Claims (1)
小クラックがクラック面積分率で５〜80％の密度で存在
する亜鉛系合金電気めっき薄膜層を下地層として持つこ
とを特徴とする、低温耐衝撃剥離性が良好で接着耐久性
にも優れた溶融亜鉛めっき鋼材および合金化溶融亜鉛め
っき鋼材。1. A low temperature characterized by having as a base layer a zinc-based alloy electroplating thin film layer in which microcracks having an average crack width of 0.001 to 5.0 μm are present at a density of 5 to 80% in terms of crack area fraction. Hot-dip galvanized steel and alloyed hot-dip galvanized steel with excellent impact resistance and excellent adhesion durability.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP33523091A JPH05171391A (en) | 1991-12-18 | 1991-12-18 | Hot-dip zinc plated steel excellent in adhesive durability |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP33523091A JPH05171391A (en) | 1991-12-18 | 1991-12-18 | Hot-dip zinc plated steel excellent in adhesive durability |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH05171391A true JPH05171391A (en) | 1993-07-09 |
Family
ID=18286201
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP33523091A Withdrawn JPH05171391A (en) | 1991-12-18 | 1991-12-18 | Hot-dip zinc plated steel excellent in adhesive durability |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH05171391A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003532808A (en) * | 2000-05-08 | 2003-11-05 | ナムローゼ・フェンノートシャップ・ベーカート・ソシエテ・アノニム | Zinc coated steel cord with improved fatigue resistance |
| JP2011007250A (en) * | 2009-06-25 | 2011-01-13 | Mazda Motor Corp | Joining structure of metallic plate material |
-
1991
- 1991-12-18 JP JP33523091A patent/JPH05171391A/en not_active Withdrawn
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003532808A (en) * | 2000-05-08 | 2003-11-05 | ナムローゼ・フェンノートシャップ・ベーカート・ソシエテ・アノニム | Zinc coated steel cord with improved fatigue resistance |
| JP2011007250A (en) * | 2009-06-25 | 2011-01-13 | Mazda Motor Corp | Joining structure of metallic plate material |
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